1. Field of the Invention
The present invention relates generally to a peptide for diagnosing, preventing and treating atherosclerosis, and a use thereof. More specifically, the present invention relates to a peptide for diagnosing, preventing and treating atherosclerosis, comprising an amino acid sequence as set forth in SEQ ID NO: 1 or SEQ ID NO: 2, and a use thereof.
2. Background Art
Atherosclerosis is a disease which involves a build-up of fat on the artery walls over time and thickening of the artery walls. There are known several risk factors that contribute to the development of atherosclerosis. Hyperlipidemia, particularly hypercholesterolemia, is primarily responsible for the pathogenesis of atherosclerosis. Further, the onset of atherosclerosis may be caused by other factors such as hypertension and diabetes. With recent changes of dietary habits into Western style involving consumption of large amounts of meat, and the gradual ageing of the population, there is now a significant increase in the incidence of atherosclerosis and atherosclerosis-related cerebro-cardiovascular diseases. Upon reviewing the development and progress of atherosclerosis, various pathogenic factors including oxidized lipids, high blood pressure and rapid blood flow result in damage of vascular endothelial cells constituting an arterial inner surface, then gradually increasing deposits of fat on vessel walls, and finally arterial thickening arising from infiltration of macrophages and T cells, progression of inflammatory reactions and proliferation of vascular smooth muscle cells. As a result, blood vessels become narrower to thereby result in poor flow of blood. When narrowing of the cardiac coronary arteries takes place, overdoing exercise may cause an insufficient supply of blood to the heart, which is then accompanied by symptomatic pain of angina pectoris. Meanwhile, where the activity of proteases, produced by macrophages within the thickened arterial walls (called atherosclerotic plaques), is high, a portion of the tissues covering plaques is partially ruptured. Here, fatty materials and peripheral proteins in plaques may flow out into the blood vessels to thereby form thrombi (blood platelets) which will lead to frequent occlusion of coronary arteries or cerebral vessels, thus causing myocardial infarction or cerebral apoplexy.
Conventional atherosclerosis diagnosis is usually made via examination of target lesions including vascular narrowing and calcification, using ultrasonography or angiography. However, the conventional diagnostic method is applicable only after substantial progress of atherosclerosis has already been made to an extent that arterial narrowing is visible by naked eyes. Further, only the medical finding of the arterial narrowing is not helpful to determine whether lesions are stable plaques or otherwise unstable plaques (vulnerable plaques or rupturable plaques) that are likely to readily disrupt. Therefore, there is a need for development of a novel diagnostic method and a diagnostic agent for the same, which are helpful and beneficial to early finding and diagnosis of atherosclerosis before appearance of conspicuous arterial narrowing, by alleviation or removal of disadvantages of these conventional atherosclerotic plaque diagnostic methods, or to determination of stability of plaques.
Meanwhile, a drug delivery system for selective delivery of a drug to affected tissues, or a targeted therapy is attracting a great deal of attention. This is because it is possible to enhance the drug efficacy while achieving a significant reduction of adverse side effects of the drug on normal tissues, even with administration of the drug at the same dose. For instance, when a certain substance (such as peptide) which is targeted to atherosclerotic plaques is conjugated to an anti-atherosclerotic drug, the resulting complex will be able to be used as an intelligent drug delivery system. Examples of a conventional atherosclerosis therapy may include a method involving chronic administration of hyperlipidemia-lowering drugs, a method involving surgical removal of plaques in severe conditions and then insertion of a metal stent to prevent restenosis or re-narrowing of blood vessels, and the like. When a selective drug delivery system to plaques is conjugated with a drug capable of inhibiting proliferation of vascular smooth muscle cells (VSMCs), as an anti-atherosclerotic drug, and a drug capable of suppressing activity of macrophages or action of protease, the resulting conjugate will be useful to prevent excessive growth or rupture of plaques.